Only one important group of drugs acting on the autonomic system is used in veterinary practice - the muscarinic antagonists. However, there are many acetylcholine analogues found in plants which can act as agonists or antagonists and poisoning is relatively common. Many obscure snake and spider toxins have interesting effects on cholinergic transmission. Clostridial toxins block the release of acetylcholine. Autonomic effects on the cardiovascular system are covered in more detail in cardiovascular pharmacology.
The neuromuscular junction is also included here, even though it is not part of the autonomic nervous system, because it relies on cholinergic transmission.
Nicotinic receptors
Muscarinic receptors
Anticholinesterases
Neuromuscular junction
diagram